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MG MGB Technical - Cool Running

I have an interesting syndrome. When it's less than 60 deg. F outside, my motor never quite warms up. It gets close, probably 10 degrees below normal. A fast run brings the motor temp down a little more than idling.

When the ambient temp rises above 60, the needle is steadfast at 'N' on the guage. As expected, it does rise above that on a long fast run in summer temps, gradually dropping to 'N' after I get off the freeway.

I expected a bad thermostat, but changing it has not made a difference. The water pump needed replacement a few months ago, and that didn't make a difference either.

This is a '74 18V with dual HIF's. Engine is slightly warmed-over - Piper 270 cam, shallow-dish pistons and Brit-Tek's "Eurospec" distributor. That and I've exchanged the cooper cans for Bob-filters. This motor has the 7-blade plastic fan. In the winter I cover the oil cooler.

Given the warm temperament of these cars, I consider this a blessing, but it has me curious. Anybody run into this before? Know what's causing it?

Thanks in advance,

Matt K.
Matt Kulka

Matt. You need to see what the actual temperatures are, not just what the gauge reads. They can vary significantly in their readings. Use a meat thermometer to see what the actual temperature is. With the engine cold, remove the pressure cap and start the engine. Feel the upper hose and, when it gets hot, insert the thermometer and see what it is reading, then cross check with the dash gauge. Then, you will know if the gauge is reading accurately. Les
Les Bengtson

Les,

Good advice, and I have done this, albeit indirectly. I verified the operation of my 180 thermostat in a pan of hot water with a meat thermometer. Having put that thermostat in the car, I found the coolant only started to flow when the gauge read exactly 'N.' So I feel the gauge is calibrated well.

I use a 195 thermostat in the winter (in a quest for more cabin heat, really). When the car warms up I have a new 'normal' needle position, a bit higher than 'N'. Which confirms for me that the gauge is operating correctly.

Next winter I'll probably just mask half the radiator and the openings in the radiator surround. As I said before, this quirk is a blessing. It just nags at me when something unusual happens that I can't account for.

Thanks for your response.

Best Wishes,

Matt K.
Matt Kulka

This thread was discussed between 17/06/2003 and 18/06/2003

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